package/linux-firmware: fix typo in firmware file for cxgb4

Trivial inversion b/g: cxbg4 -> cxgb4

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Jeremy Kerr <jk@ozlabs.org>
Acked-by: Jeremy Kerr <jk@ozlabs.org.
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/linux-firmware/linux-firmware.mk

@@ -157,7 +157,7 @@ endif
 ifeq ($(BR2_PACKAGE_LINUX_FIRMWARE_CXGB4),y)
 LINUX_FIRMWARE_FILES += \
 	cxgb4/t4fw-1.9.23.0.bin \
-	cxbg4/t4fw.bin
+	cxgb4/t4fw.bin
 LINUX_FIRMWARE_ALL_LICENSE_FILES += LICENCE.chelsio_firmware
 endif